Pelagic+Zone

//by Trevor Dinh, Jenny Guan, and Duy Le (4th period)//

The word, pelagic comes from the Greeks language which translates to "open sea" which what the pelagic zone is.The pelagic zone is a division of the ocean that includes all the regions except for those on the surface and on the sea floor. This biome consists of the largest volume out of all the inhabited environments on earth, with 1.37 billion cubic kilometers of ocean water. It's divided into sub-zones similar to the division of the atmosphere: there are the epipelagic, mesopelagic, bathypelagic, and abyssalpelagic zones.

=Fauna=

epipelagic zone

 * marine mammals: seals, whales, dolphines, porpoises, manatees, dugongs, otters, walruses

The word meso comes from the Greek language which translates to "middle".
 * media type="custom" key="27112814" width="108" height="108" align="left" || ===mesopelagic zone ("the twilight zone")===
 * becomes very dark due to limited sunlight
 * animals can eat larger animals because they have the advantage of sharper teeth with expandable jaws and stomachs
 * bioluminescent animals
 * food is scarce, so some migrate to the surface at night to feed
 * reliance on food that falls from upper layers
 * organisms survive here by having efficient gills or minimizing their movements ||

bathypelagic zone
The word bathys is a stem of the Greek language meaning "deep".
 * virtually no light except for from bioluminescent organisms
 * food only trickles down from above
 * normal marine groups: fish, mollusks, jellies, crustaceans
 * sperm whales dive when hunting giant squid
 * most animals are black or red due due to faint penetration of green light

abyssopelagic zone
The word abyss originates from the Greek language meaning "bottomless".
 * inhospitable to most organisms
 * the few organisms that do live here though are either transparent or don't have eyes due to almost no sunlight

=Flora= No more autotrophs live in the mesopelagic zone and deeper. The few listed live in the upper zone (epipelagic).
 * surface seaweed
 * phytoplankton - the base food source to all marine animals found in the upper levels of the pelagic
 * diatoms - are a major group of algae and some common types are phytoplankton
 * dinoflagellates - most are autotrophs as they are a component of phytoplankton

=**Seasonal Temperatures**=

epipelagic zone

 * temperatures can be as high as 97º Fahrenheit in the Persian gulf and as low as 28ºF near the poles.
 * because the ocean covers such an immense area, the temperatures vary a lot
 * although precipitation does not affect the temperature of the zone (because of the massive amount of water), rain can affect its salinity.
 * this level is the warmest level overall because it has contact with sunlight
 * average temperature overall is 68ºF, but is affected by factors such as altitude and latitude.

=Human Impacts and Interactions=
 * because of the high pressure of deep water, physical human interaction is limited
 * over-fishing, ocean acidification, and growing low oxygen zones could wipe out entire species
 * there is little fishing done in the mesopelagic zones and further downward so direct human impact is minimal
 * however, by over-fishing other forms of fish, people can disrupt the food chain and the consequences can be seen on organisms living this deep
 * boat pollution from fishing leaves lots of dangerous toxins that reach the upper pelagic zone (epipelagic or mesopelagic) killing organisms that already depend on the little oxygen

=Sources= http://www.britannica.com/EBchecked/topic/449062/pelagic-zone http://marinebio.org/oceans/open-ocean/ http://oceanlink.info/biodiversity/deepsea/deepsea.html http://www.mbari.org/news/news_releases/2010/deep-conservation/deep-conservation-release.html http://montereybay.noaa.gov/sitechar/pelagic5.html http://www.untamedscience.com/biology/biomes/pelagic-biome/